Molten metal transfer system



Feb. 24, 1970 J. l.. DONAHUE 3,497,189

MOLTEN METAL TRANSFER SYSTEM Filed April 29, 1968 3 Sheets-Sheet 1 EEE Q: /0

A TTORNEVS Fb. 24, 1970 J. L.. DONAHUE I 3,497,189

MOLTEN METAL TRANSFER SYSTEM Filed April 29, 196s :5 sheets-sheet 2 I BY /j/f; M M

ATTORNEYS Feb. 24, 1970 J. L. DONAHUE 3,497,189

MOLTEN METAL TRANSFER SYSTEM Filed April 29. 1968 5 Sheets-Shea?l 3 2&2 E C "'20 Vf f6 /NVENTOR ATTORNEYS United States Patent O 3,497,189 MOLTEN METAL TRANSFER SYSTEM James L. Donahue, 24312 Panama, Warren, Mich. 48091 Filed Apr. 29, 1968, Ser. No. 724,696 Int. Cl. F27d 3/14, 15/00; B22d 39/00 U.S. Cl. 263-11 15 Claims ABSTRACT F THE DISCLOSURE A metal transfer system for transferring molten metal from a melting pot to a ladle. A pump submerged in the molten metal is operated periodically to apply the pressure to t-he molten metal in a conduit extending from the melting pot to a ladle having a Weir. A second conduit surrounds the first conduit and air at an elevated temperature is directed around the ladle and through the second conduit to elevate the temperature of the molten metal above the temperature of the molten metal in the pot and maintaining it at elevated temperature. Periodic operation of the pump causes the molten metal in the ladle to overflow and feed predetermined quantities of molten metal into a mold.

This invention relates to the transferring of molten metal from a melting pot to a mold.

In the manufacture of parts from molten metal such as the grids of a battery wherein molten metal is transferred from a melting pot to a mold, one of the problems is that the molten metal must be at a suiciently elevated temperature to insure proper flow of the metal into the various' parts of the mold. In connection with certain molten metals, the elevation of an exposed body of metal to a suficiently high temperature results in oxidation and other adverse chemical effects. In addition, where the molding process is interrupted for any period of time, the problems of control of the temperature of the molten metal becomes more difficult.

Among the objects of the present invention are to provide a novel method and apparatus for transferring molten metal from a melting pot to a mold wherein in the movement from a melting pot to the mold, the temperature of the molten metal is controlled; wherein the temperature of t-he mold can be elevated; wherein a simple and effective means is provided for carefully controlling the temperature of the molten metal; which system is easy to maintain and requires a minimum of maintenance.

In the drawings:

FIG. 1 is a part sectional plan view of a system embodying the invention.

FIG. 2 is a partly diagrammatic vertical sectional view of a portion of the system.

FIG. 3 is a fragmentary side elevational view of a portion of the system.

FIG. 4 is a partly diagrammatic fragmentary elevational view of another portion of the system.

FIG. 5 is a fragmentary sectional view taken along the line 5-5 of FIG. 3.

FIG. 6 is a diagrammatic view of the form of the invention shown in FIGS. 1-5.

FIG. 7 is a diagrammatic view of a modified form of the invention.

Referring to FIGS. l and 2, in accordance with the system, molten metal is to be transferred from a melting pot 10 to a ladle 11 for periodic feeding to a mold 12. This is achieved by utilizing a submerged pump 13 which pumps fluid through a pipe 14 and a conduit 15 to the ladle 11 which is at a higher level than the level of molten metal in pot 10. The ladle 11 includes a Weir 16 (FIG. 5) so that upon periodic operation of the pump 13, the molten metal in the ladle 11 is caused to overflow and feed a predetermined quantity of molten metal through the mold 12. Pump 13 can be of various types such as a reciprocating piston type pump.

In accordance with the invention, the conduit I is surrounded by a second pipe or conduit 17 that extends from the ladle area to the pipe 14. A housing 18 surrounds the ladle 11 and has an opening 19 communicating with the conduit 17.

Air from a blower 20 is directed downwardly through a pipe 21 into a direct fired burner 22. A pipe 22a surrounds the burner and serves to prevent direct impingement of the air with the flame of the burner 22. A heating chamber 23 surrounds the burner 22 and the air flows axially and mixes with the hot gases of combustion and thereafter passes downwardly through a pipe 24 to the housing 18. A deflector 25 within housing 18 extends horizontally into overlying relationship with the ladle 11 and overlies the ladle so that the hot gases are caused to flow laterally as viewed in FIG. 3 around the ladle and then through the opening y19 to the second conduit 17. The hot gases flow along the conduit 17 in counter flow relation to the direction of movement of the molten metal in the conduit 15 to a vertical stack 26 which is at the end of the conduit 17 substantially overlying the melting pot 10.

It has been found that by heating the air to an elevated temperature, the temperature of the molten metal in the conduit 15 can be elevated above the temperature of the molten metal in the melting pot 10 and can be maintained at the elevated temperature. Since the molten metal at the elevated temperature is completely enclosed either in the pipe 15 or in the ladle 11, the chances of oxidation or other detrimental effects occurring at the elevated temperature are minimized whereas the temperature of t-he molten metal in the melting pot 10 is maintained at a lesser temperature so that there is lesser possibility of such adverse effects.

lFurther by controlling the temperature of the air, the temperature of the molten metal in the conduit 15 and the ladle can be controlled within very close limits.

Thus, for example, in the case of molten metal for making the battery grids, such as a lead alloy, the ternperature of the alloy maybe at approximately 850 degrees F. in the melting pot and its temperature can be elevated so that at the pouring point, the temperature is 1100-1150 degrees F.

For optimum results, the conduit 17 should be insulated by insulation I.

The form of the invention heretofore described is shown diagrammatically in FIG. 6.

Another form of the invention is shown diagrammatically in FIG. 7 wherein molten metal is directed by a pump P through pipe 15 to the ladle l1 as in the previous form. The pipe 15 is surrounded by a conduit 17'. In this form, the air from a blower is directed to a burner 31 and mixed with the hot gases thereof and then passed to a manifold 32. The manifold 32 is adapted to supply various sections of the conduit 17. Thus, the hot gases flow from manifold 32 through a pipe 33 to surround a section 34 of the conduit 17'. The ow through this section is divided to exhaust at each end 35, 36. Similarly, an intermediate section 37 is supplied through a pipe and the flow is divided to exhaust 39, 40. Finally, the last section 41 is supplied through a pipe 42 and the ow is divided to exhausts 42, 43, the latter occurring in the area of the ladle 11. By the form of the invention shown in FIG. 7, it is possible to control the temperature of various sections of the conduit 17'.

Valves or adjustable orifices 36', 39', 40', 43' and L4 are provided in connection with each of the sections ind may be utilized to control the ow through each secion so that the temperatures of the sections are conrolled. The temperatures may be the same in all of the ections or may be varied in accordance with the requirenents. The form of the invention shown in FIG. 7 is paricularly applicable to installations wherein there is a sub- ;tantial distance between the melting pot and the point of lelivery of the molten metal.

In accordance with the invention, in each of the forms )f the invention, an accurate control of the temperature )f the molten metal is achieved at all points between the iurface of the molten metal in the pot 10 and the point it which the molten metal leaves the transfer system.

Although the invention has been described in connec- :ion with a fixed weir type ladle, other methods of delivery :an be utilized. For example, a movable ladle can be ltilized to which the molten metal is delivered continu- )usly or intermittently or other feeders such as valves :an also be used.

I claim:

1. The method of transferring molten metal which comarises directing molten metal in a closed path from a source to a mold,

passing fluid in heat exchange relationship with said metal,

and continuously heating said uid before passage into heat exchange relationship with the metal,

confining said molten metal in an intermediate mass in advance of the mold,

periodically permitting a portion of the molten metal to flow from said intermediate mass to the mold,

and continuously directing a portion of the fluid into heat exchange relationship with said intermediate mass,

said fluid flowing into heat exchange relationship with said molten metal owing in said closed path after it has been in heat exchange relationship with said intermediate mass.

2. The method set forth in claim 1 including the step of heating said uid to a higher temperature such that the temperature of the molten metal is elevated during its travel from the source to the mold.

3. The method set forth in claim 2 wherein said fluid flows in a direction counter to the direction of flow of said molten metal.

4. The method set forth in claim 1 wherein said step of directing molten metal in a closed path is performed by applying pressure to a portion of the molten metal at said source.

5. In the manufacture of battery grids, the method of transferring molten metal which comprises directing molten metal in a closed path from a source to a mold,

passing fluid in heat exchange relationship with said metal,

and continuously heating said fluid before passage into heat exchange relationship with the metal,

heating said fluid to a higher temperature such that the temperature of the molten metal is elevated during its travel from the source to the mold,

said fluid flowing in a direction counter to the direction of flow of said molten metal,

confining said molten metal in an intermediate mass in advance of the mold,

periodically permitting a portion of the molten metal to ow from said intermediate mass to the mold,

and continuously directing a portion of the fluid into heat exchange relationship with said intermediate mass.

6. The method set forth in claim 5 wherein said uid ilows into heat exchange relationship with said molten metal flowing in said closed path after it has been in heat exchange relationship with said intermediate mass.

7. The method set forth in claim 6 wherein said step of directing molten metal in a closed path is performed by applying pressure to a portion of the molten metal in said source.

8. The combination comprising a source of molten metal at a predetermined temperature,

a ladle having a charge delivering opening,

a first conduit having one end thereof submerged in said source and the other end thereof extending to said ladle,

delivery means for directing molten metal from said source to said ladle,

a second conduit surrounding the major portion of said rst conduit,

means for directing fluid at an elevated temperature through said second conduit into heat exchange relationship with said first conduit such that the temperature of the molten metal in said conduit is elevated to a greater temperature than the temperature of the molten metal in said source,

and means for directing said uid into heat exchange relationship with the molten metal in said ladle.

9. The combination set forth in claim 8 including means interconnecting said last-mentioned means and said second conduit surrounding said first conduit so that there is communication between the area surrounding the ladle and the interior of the second conduit.

10. The combination set forth in claim 9 wherein said fluid is directed to ow counter to the direction of flow in said conduit.

11. The combination comprising a source of molten metal at a predetermined temperature,

a ladle having a charge delivering opening,

a first conduit having one end thereof submerged in said source and the other end thereof extending to said ladle,

delivery means for directing molten metal from said source to said ladle,

a second conduit surrounding the major portion of said first conduit,

and means for directing fluid at an elevated temperature through said second conduit into heat exchange relationship with said first conduit such that the temperature of the molten metal in said conduit is elevated to a greater temperature than the temperature of the molten metal in said source,

said fluid comprising air,

said means for directing fluid including a blower and a heater through which the blower directs the air.

12. The combination set forth in claim 11 wherein said blower and heater are arranged such that the air ows through said wall surrounding said conduit in a direction opposite to the direction of flow of molten metal in said conduit.

13. The combination set forth in claim 12 including a housing surrounding said ladle,

said housing having the interior thereof communicating with the interior of said second conduit surrounding said first conduit so that a portion of the iluid is directed against said ladle.

14. The combination comprising a source of molten metal at a predetermined temperature,

a ladle having a charge delivering opening,

a first conduit having one end thereof submerged in said source and the other end thereof extending to said ladle,

delivery means for directing molten metal from said source to said ladle,

a second conduit surrounding the major portion of said first conduit,

and means for directing fluid at an elevated temperature through said second conduit into heat exchange 5 6 relationship with said first conduit such that the tem- References Cited perature of the molten metal in said conduit is ele- UNITED STATES PATENTS vated to a greater temperature than the temperature 1,522,765 1/1925 Wilke 263-11 of the molten metal 1n said source, 1,790,820 2/1931 Kutchka 263 11 a header and means for selectively directing fluid from 5 3,398,697 8/1968 Rader 164 312 said header to various sections of said second conduit. JOHN J. CAMBY, Primary Examiner 15. The combination set forth in claim 14 including E means for selectively controlling the flow 0f uid through 10 164 337 U'S C1' X'R' each of said sections. 

